Three position status indicator



June 28, 1966 KLElN 3,258,763

THREE POSITION STATUS INDICATOR Filed July 19, 1963 2 Sheets-Sheet 1 a) I 0 [0 Q 33 O I: 40 o 0 n O o I 53 F o 0 42 33 "i O Q I2 35 2025 o 43 39 3 INVENTOR .Fzgj

DIETRICH J. KLE|N BY aim 6 a. a LOG/+4614.

ATTORNEYS June 28, 1966 D. J. KLEIN THREE POSITION STATUS INDICATOR 2 Sheets-Sheet 2 Filed July 19, 1963 INVENTOR DIETRICH J. KLEIN BY l afdomt R waif H3 ATTORNEYS United States Patent This invention relates to multiple position relays having at least three separate stable switching positions and more specifically, it relates to status indicators for visually displaying multiple-position signals.

Simple bistable memory devices, such as latching relays and-flip flop circuits, are well known in the art, but tristable or multistable status devices have been significantly complex. An even greater disadvantage is the requirement for continuous power in many of the pr or art multi state devices used as memory devices to maintain the selected status.

Amemory device for general application or for use in status indicators must "be capable of performing outside work by operation of switching devices. Non-destructive readout characteristics are also desirable, so that multiple readouts of the same condition or continuous readout may be provided without restoring the status in the memory device.

One example of a tristable visual display device is a room status indicator for a hotel, which can signalthat a room is occupied, free or in need of maid services. Such an indication should be capable of remote as well as local display. Thus, it can be monitored at the room door or at the hotel desk, and possibly also in the maids quarters. If such a display device requires continuous power to store the status it generates excessive heat, is more subject to failure and is expensive since more rugged components must be used in construction for continuous rather than momentary operation.

A further requirement of a status indicator is the lack of confusion in identification. Display systems become confusing when mental decisions must be made to interpret the positions of a large number of lamps where information is contained relative to the particular display position.

Accordingly, it is an object of this invention to provide improved multista'ble state memory means.

Another object of the invention is to provide reliable and simplified means for visually indicating a multipleposition status.

Thus, in accordance with an embodiment of the invention, a tristable state status indicator is provided employing a simplified memory relay. The status indicator may be operated manually by closing one of three momentary contact switches, which accordingly operate the memory relay to a corresponding stable static (non- I energized) storage position.' The relay has accompanying switch blades so that a corresponding annunciator lamp of a distinctive color is energized in each storage position, The lamp signals are concentrated at a single panel position to provide a fool-proof status indication of the selected relay state.

Simplified relay construction is afforded by providing a detented'movable magnetic core with a plurality of actuating solenoids arranged along the core axis to in-- fiuence the movement of the core to a detented position determined by the combination of solenoids energized momentarily. The core is shaped to operate as a cam for one or more sets of movable switching springs provided with a corresponding cam-rider extension.

. Further features and objects of the invention will be found throughout the following detailed description of the invention as displayed in the accompanying drawing, wherein:

FIGURE 1 is a schematic circuit diagram of a triposition status indicator embodiment of the invention;

FIGURE 2 is a front panel view of an assembled status indicator; 2

FIGURE 3 is a top plan view of an assembled status indicator;

FIGURE 4 is a plain view, partly in section, of a memory relay alforded in accordance with the invention;

FIGURES 4A and 4B are fragmentary views of the relay of FIGURE 4 in different operating positions;

FIGURE 5 is an elevation view, partly in section, of a portion of the relay of FIGURE 4; and

FIGURES 6A, B and C are fragmentary sketches of a -modified relay switching embodiment in various operating positions.

The status indicator of FIGURES 1-3 is of the type useful in providing signals for the status of a room in a hotel. Thus, colored lamps 10,11, 12 respectively, for example, red, green and yellow, may indicate maid service required, room free for occupancy, and room occupied. The circuit leads 13, 14, 15 for the lamps and the lamp panel portion 16 may be located at several positions, such as with the room clerk, at the room door and in the maids quarters. Annunciator lamps 10, 11 and 12 may be low powered neon lamps, for example operated by a voltage source such as battery 18 or an equivalent volt A.C. line with suitable current limitmg resistors.

Only one lamp is energized in accordance with the positions of relay contacts 20 and 21. Thus, in the status position shown lamp 12 is energized, but if contact 21 is moved, lamp 11 isenergized and if contact 20 is moved, lamp 10 is energized. Solenoid winding 23 serves to movecontact 20 from its rest position to its latching position energizing lamp 10, when energized by momentary contact 31 in key panel 32, as'provided from a power source represented by battery 29. Similarly, solenoid 25 is energized by operation of momentary contact 35 from power source represented by battery 28. Batteries 28 and 29 may be one and the same if so desired.

When the remaining key 33 is momentarily closed it serves to operate both solenoids 23 and 25 from power source 28 to return both contacts to the rest position 33 and 35 could be labeled red, yellow and green to correspond with the lamp designation, or such other designation as desired to indicate the choice of status.

To provide a single status indication on the front panel, a light pipe such as plastic prism 39 is employed with a front panel viewing window 40. Since each lamp has a distinctive color filter 41, 42 or 43, and is energized alone, the front panel window will displaya single color at a single position, so that reading of numbers or mental interpretation of the position will not be required.

The solenoid arrangement as shown in FIGURES 46 employs a soft magnetic core 50, which is held in three stable positions by detent mechanism 51 which engages notches 52 in the core. The core is shaped to have a cam surface 53, which operates on cam rider 54 to move the switch springs 55.

Solenoids 23 and 25 are arranged along the axis of core 50 so that they tend to center the core whenever energized in series. Thus, as solenoid core 25 is energized, the core is moved to its leftmost latching or detented position as sketched in FIGURE 4A. Conversely, when solenoid coil 23 is energized the core is moved to its rightmost latching position as shown in FIGURE 4B. When both solenoid coils 23 and 25 are energized in series, the core 50 is centered and contact assemblies 20, 21 are in their rest position. 7

End stops 71 and 72 are provided to limit the movetion of thes'olenoid windings need not be critical since an overshoot will not occur.

. It is to be noted that because of the constructional features described, the relay can be quite inexpensive. For example, the solenoids may be designed for momentary operation rather than continuous duty because of the static storage vfeatureincorporated.

In FIGURE 6, the cam-core action is shown with three switching steps on a single switch assembly, accomplished by providing an intermediate cam surface 60, which actuates the cam rider 54 in position B to provide open switch contacts 62. The principles of this invention are thus extendable to include switching variations generally useful in obtaining a status indication over'a plurality of memorized positions, requiring no stand-by power except for lamp excitation.

Having therefore described the nature of this invention, features of novelty are set forth in detail in the following claims.

-I claim:

1. A three position electromagnetic relay switching circuit comprising in combination, two actuating solenoids arranged side by side along a common axis, a soft magnetic core member longer than either solenoid and freely movable along said axis to a centered position within either solenoid under the influence of the magnetic field produced by either solenoid when energized, detent structure mounted between said solenoids comprising a spring biased cam rider and three cammed surface indentations in said core member to receive the cam rider and thereby frictionally hold the core in three stable positions without energization of the solenoid, said cam rider and cammed surface being fashioned to permit said core to attain a diflerent stable position by frictional displacement'of the cam rider as said solenoids are energized to @Hter the core in a different position, and three temporary energization circuits for establishing said three stable positions respectively comprising a momentary switch coupling an energizing source independently to each sole- ,noid to center thecore therein at the two stable end positions, and a third momentary switch coupling an energizing source to both solenoids simultaneously to center the core within both solenoids at the center stable position.

2. Annunciator means as defined in claim 1 including switching contacts having a spring with a cam rider extension disposed to ride the cammed surface of said core to provide distinctive switching circuits for each rest position, three lamps of different colors, a plastic prism displaying the light from each of the three lamps at a single viewing panel position, and connections through said switching circuits to light lamps of different colors for each stable position.

3. A tri-stable memory device comprising two adjacent solenoid windings with a magnetic core having a cammed surface movable within the windings to center in three stable positions respectively within the two solenoids at end positions and intermediate the two solenoids at a center position, a spring biased frictional detent mechanism comprising a cam rider and a mating cammed surface -on said core to hold the core removably in each of said positions without energization of said solenoids, spring biased switch contacts having a cam rider engaging said cammed surface of the core to provide three distinctive switching circuits for the respective stable positions, and circuit means connecting said two solenoid windings for moving said core to one of the stable positions against the detent friction respectively to an energizing source singly to establish the two end core positions and together to establish the intermediate core position.

References Cited by the Examiner UNITED'STATES PATENTS 807,859 12/1905 Patten 340-316 1,183,170 5/1916 Damson 317- X 1,365,329 1/1921 Lewis.

2,057,380 10/1936 Keefe 200-98 2,446,855 8/1948 Seibel 317-190 2,508,051 5/1950 Warren 340-332 X 2,589,569 3/1952 Peter 340-380 2,611,018 9/1952 Thorp 340-380 X 2,658,123 11/1953 Von Stoeser 200-98 2,659,838 11/1953 Rocher 340-332 X 2,895,090 7/1959 Short 317-188 2,980,890 4/19'61 Staten 340-286 X 3,070,730 12/1962 Gray 317-190 3,071,664 1/1963 Priesemutly 317-188 X 3,155,957 11/1964 Parissi 340-332 X FOREIGN PATENTS 1,035,771 8/ 1958 Germany.

422,071 1/1935 Great Britain.

NEIL C. READ, Primary Examiner. R. M. GOLDMAN, Assistant Examiner. 

1. A THREE POSITION ELECTROMAGNETIC RELAY SWITCHING CIRCUIT COMPRISING IN COMBINATION, TWO ACTUATING SOLENOIDS ARRANGED SIDE BY SIDE ALONG A COMMON AXIS, A SOFT MAGNETIC CORE MEMBER LONGER THAN EITHER SOLENOID AND FREELY MOVABLE ALONG SAID AXIS TO A CENTERED POSITION WITHIN EITHER SOLENOID UNDER THE INFLUENCE OF THE MAGNETIC FIELD PRODUCED BY EITHER SOLENOID WHEN ENERGIZED, DETENT STRUCTURE MOUNTED BETWEEN SAID SOLENOIDS COMPRISING A SPRING BIASED CAM RIDER AND THREE CAMMED SURFACE INDENTATIONS IN SAID CORE MEMBER TO RECEIVE THE CAM RIDER AND THEREBY FRICTIONALLY HOLD THE CORE IN THREE STABLE POSITIONS WITHOUT ENERGIZATION OF THE SOLENOID, SAID CAM RIDER AND CAMMED SURFACE BEING FASHIONED TO PERMIT SAID CORE TO ATTAIN A DIFFERENT STABLE POSITION BY FRICTIONAL DISPLACEMENT OF THE CAM RIDER AS SAID SOLENOIDS ARE ENERGIZED TO CENTER THE CORE IN A DIFFERENT POSITION, AND THREE TEMPORARY 